The present invention relates to a thermoplastic resin composition containing a modified polyolefin and having excellent mechanical properties such as impact resistance, etc. It also relates to a thermoplastic resin composition reinforced with inorganic fillers and having improved impact resistance, heat resistance, etc. without suffering from discoloration. It further relates to a method of producing a modified polyolefin-containing composition and a method of producing a modified polyolefin-containing graft copolymer.
Recently, engineering plastics such as polyamide resins, polyesters, polycarbonates, etc. have been finding various applications. Specifically, polyamide resins are light and have excellent heat resistance, chemical resistance, workability, mechanical strength, etc. However, the polyamide resins are poor in mechanical properties such as impact resistance, etc., and have a large water absorption property. Polyesters such as polyethylene terephthalate, polybutylene terephthalate, etc. have excellent heat resistance, mechanical strength, etc. However, the polyesters are poor in mechanical properties such as impact resistance, etc. Polycarbonates also have excellent mechanical properties, particularly in impact resistance. However, when molded articles made of polycarbonates become larger, their impact resistance drastically decreases.
Apart from them, polypropylene has excellent mechanical strength, moldability, chemical resistance, etc., but it is poor in secondary formability, adhesiveness, paintability, etc., because it is a non-polar material. On the other hand, polystyrene resins have good adhesiveness. Particularly, styrene-acrylonitrile copolymers show good chemical resistance, mechanical strength and heat resistance. Accordingly, it is expected to obtain a combination of good properties of the polystyrene resins and polypropylene by blending them. However, since the polystyrene resins have a poor compatibility with polypropylene, the resulting blends show poor surface peel resistance and impact resistance.
In view of the above, various proposals have been made to provide blends of these resins with modified polyolefins for the purpose of improving their mechanical and physical properties.
With respect to compositions of polyamides and modified polyolefins, Japanese Patent Publication No. 55-44108 discloses a reinforced thermoplastic resin composition consisting essentially of 60-99 weight % of a polyamide resin matrix phase having a number-average molecular weight of at least 5,000; and 1-40 weight % of another phase having a particle size of 0.01-1.0 .mu.m and consisting of a particular branched or linear polymer bonded to the polyamide resin matrix, the particular branched or linear polymer being a modified polyolefin or a modified olefinic elastomer, which may contain other unsaturated monomers. However, since the modified polyolefin or olefinic elastomer is modified with unsaturated carboxylic acids, etc., and since such modified polyolefin or olefinic elastomer shows a relatively poor compatibility with the polyamide resin, sufficiently high impact strength cannot be achieved.
Japanese Patent Laid-Open No. 60-219257 discloses a thermoplastic resin composition comprising (A) 99.5-60 weight % of a polyamide resin and (B) 0.5-40 weight % of an ethylenic copolymer, the ethylenic copolymer (B) being a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (c) 0.5-1.5 weight % of maleic anhydride, or a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (d) 0.5-1.5 weight % of glycidyl methacrylate and/or glycidyl acrylate. However, since the ethylenic copolymer shows a relatively poor compatibility with the polyamide resin, sufficiently high impact strength cannot be achieved.
Japanese Patent Laid-Open No. 54-123158 discloses a polyolefin resin composition comprising a modified polyolefin grafted with unsaturated carboxylic acids (optionally diluted with polyolefin), a polyamide resin and a filler. Japanese Patent Laid-Open No. 59-232135 discloses a polyolefin resin composition comprising a modified polyolefin grafted with unsaturated carboxylic acids, a polyamide resin and a crystalline polyolefin. Japanese Patent Laid-Open No. 60-118735 discloses a polyolefin resin composition obtained by melt-blending 10-99 parts by weight of a polyamide resin and 90-1 parts by weight of a modified polyolefin containing 0.01-5.0 weight % of an unsaturated carboxylic acid. However, these unsaturated carboxylic acid-modified polyolefins have a poor compatibility with the polyamide resins.
Japanese Patent Laid-Open No. 60-49018 discloses a polyamide-polyolefin resin composition obtained by melt-blending 10-100 parts by weight of a polyamide resin, 3-100 parts by weight of a polyolefin, 0.001-5.0 parts by weight of an unsaturated carboxylic acid or its derivatives, and 0.01-2.0 parts by weight of a peroxide, per 100 parts by weight of the total amount of the polyamide resin and the polyolefin. In this case too, a sufficiently high compatibility cannot be achieved.
With respect to compositions of polyesters and modified polyolefins, Japanese Patent Publication No. 58-47419 discloses a resin composition produced by melt-blending 100 parts by weight of a saturated polyester constituted by a dicarboxylic acid component containing 40 mol % of a terephthalic acid and a diol component and having an intrinsic viscosity of 0.5-3.0 with 1-150 parts by weight of a copolymer comprising 70-99.5 weight % of an .alpha.-olefin; 0.5-20 weight % of a glycidyl methacrylate and 0.1-30 weight % of vinyl acetate.
Japanese Patent Laid-Open No. 60-58447 discloses a thermoplastic resin composition comprising polypropylene (A), a thermoplastic polyester (B), a modified propylene-.alpha.-olefin random copolymer (C), a styrene-butadiene block copolymer hydrate (D), and an inorganic filler (E), the modified propylene-.alpha.-olefin random copolymer (C) being produced by grafting (G) a propylene-.alpha.-olefin random copolymer having a crystallization degree determined by X-ray of 0-30 weight % and a propylene content of 50-70 mol %, with 0.01-5 weight % of a graft monomer selected from unsaturated carboxylic acids and their derivatives, the amount of each component, per 100 parts by weight of the total amount of (A)+(B), being 1-80 parts by weight of (C), 1-50 parts by weight of (D), and 5-150 parts by weight of (E).
Japanese Patent Laid-Open No. 60-219254 discloses a thermoplastic resin composition comprising (A) 99.5-60 weight % of a saturated polyester and (B) 0.5-40 weight % of an ethylenic copolymer, the ethylenic copolymer (B) being a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (c) 0.5-1.5 weight % of maleic anhydride, or a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (d) 0.5-1.5 weight % of glycidyl methacrylate and/or glycidyl acrylate.
Japanese Patent Laid-Open No. 1-193351 discloses an aromatic polyester composition comprising 100 parts by weight of a particular aromatic polyester capable of forming an anisotropical molten phase and 0.1-60 parts by weight of an olefinic polymer comprising an .alpha.-olefin and a glycidyl ester of an .alpha., .beta.-unsaturated acid.
Japanese Patent Laid-Open No. 1-236266 discloses a thermoplastic polyester resin composition comprising (A) 100 parts by weight of a thermoplastic polyester resin; (B) 1-100 parts by weight of a polymer or copolymer consisting of one or more of a vinyl cyanide compound, an acrylate, a methacrylate, an aromatic vinyl compound, etc.; (C) 0.5-80 parts by weight of an olefinic copolymer comprising an .alpha.-olefin and a glycidyl ester of an .alpha.,.beta.-unsaturated acid or a graft copolymer formed by grafting the above olefinic copolymer with a monomer selected from a vinyl cyanide compound, an acrylate, a methacrylate, an aromatic vinyl compound, etc.
Japanese Patent Laid-Open No. 51-144452 discloses a resin composition comprising 60-99 weight % of a matrix resin consisting essentially of a polyester matrix resin and/or a polycarbonate matrix resin; and 1-40 weight % of a modified ethylenic copolymer grafted with an .alpha.,.beta.-ethylenic unsaturated carboxylic acid or its derivative.
In the above polyester compositions, however, the modified polyolefins are also poor in compatibility with the polyesters.
In addition, as compatibilizers for polyesters and polypropylenes, various proposals have been made to add epoxy group-containing copolymers to the thermoplastic resin compositions comprising polypropylenes and polyesters.
Japanese Patent Laid-Open No. 61-60744 discloses a thermoplastic resin composition comprising 100 parts by weight of a resin composition comprising (A) 10-90 weight % of polypropylene, (B) 90-10 weight % of a saturated polyester resin, and (C) 2-30 parts by weight of an epoxy group-containing copolymer.
Japanese Patent Laid-Open No. 61-60746 discloses a thermoplastic resin composition comprising 100 parts by weight of a resin composition comprising (A) 50-90 weight % of a modified polypropylene with or without polypropylene, (B) 50-10 weight % of a saturated polyester resin, and (C) 2-30 parts by weight of an epoxy group-containing copolymer.
However, in these thermoplastic polyester compositions, a sufficient improvement in flexural modulus and impact resistance cannot be achieved. Also, the polypropylene and the polyester are not sufficiently compatible with each other even in the presence of the above modified polyolefins.
With respect to compositions of polycarbonates and modified polyolefins, Japanese Patent Laid-Open No. 60-215052 discloses a thermoplastic resin composition comprising (A) 99.5-60 weight % of a polycarbonate resin, and (B) 0.5-40 weight % of an ethylenic copolymer, the ethylenic copolymer (B) being a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (c) 0.5-1.5 weight % of maleic anhydride, or a terpolymer consisting of (a) 55-94 weight % of ethylene, (b) 5-40 weight % of a particular alkoxy alkyl acrylate and (d) 0.5-1.5 weight % of glycidyl methacrylate and/or glycidyl acrylate.
Japanese Patent Laid-Open No. 64-75547 discloses a thermoplastic resin composition comprising (a) 95-5 weight % of an aromatic polycarbonate, (b) 5-95 weight % of a polyolefin, and (c) 2-100 parts by weight of a modified polyolefin and 2-100 parts by weight of a polybutylene terephthalate per 100 parts by weight of the total amount of the aromatic polycarbonate and the polyolefin. The modified polyolefin is a random, block or graft copolymer of olefin and an unsaturated carboxylic acid.
In these polycarbonate resin compositions, however, the modified polyolefins modified with unsaturated carboxylic acids or their derivatives have a poor compatibility with the polycarbonates.
With respect to polyolefin-based compositions, Japanese Patent Laid-Open Nos. 64-87645 and 1-174550 disclose compositions of polypropylene, polystyrene resins, and compatibilizers such as styrene-unconjugated diene block copolymers, etc. However, such compabilizers are ineffective particularly when styrene-acrylonitrile copolymers are used as the polystyrene resins.
With respect to the blending of polypropylene with inorganic fillers such as glass fibers, Japanese Patent Laid-Open No. 56-55450 discloses a polyolefin composition comprising (a) a modified polyolefin grafted with an unsaturated carboxylic acid or its anhydride or a mixture of such a modified polyolefin with an unmodified polyolefin, (b) an inorganic filler such as glass fibers, talc, mica, etc., and (c) a nucleating agent or a nucleating agent+a thermal deterioration-preventing agent.
Japanese Patent Laid-Open No. 58-42639 discloses a polyolefin composition comprising (a) a modified polyolefin grafted with an unsaturated carboxylic acid or its anhydride or a mixture of such a modified polyolefin with an unmodified polyolefin, (b) glass fibers, and (c) calcium silicate fibers.
However, since these compositions containing modified polyolefins grafted with unsaturated carboxylic acids or their derivatives are discolored to a yellowish color, their applications are restricted in many cases. In addition, since the modified polyolefins grafted with unsaturated carboxylic acids or their derivatives are likely to be decomposed in the process of graft polymerization, they fail to have sufficiently large molecular weights.